Post-Tropical Cyclone SEYMOUR Forecast Discussion (Text)

000
WTPZ45 KNHC 280835
TCDEP5
POST-TROPICAL CYCLONE SEYMOUR DISCUSSION NUMBER 21
NWS NATIONAL HURRICANE CENTER MIAMI FL EP202016
200 AM PDT FRI OCT 28 2016
The cyclone has lacked organized deep convection within 60-100 n mi
of its center for over 12 hours, and no longer qualifies as a
tropical cyclone. Since Seymour has become a post-tropical remnant
low, advisories are being discontinued. Subjective Dvorak
classifications from TAFB and SAB along with scatterometer data
indicated an intensity of near 35 kt at 0600 UTC. Assuming some
additional spindown of the cyclone since then, the advisory
intensity is set at 30 kt. The low will be moving through an
extremely hostile environment of southwesterly shear of 40-45 kt and
SSTs cooler than 23 deg C during the next couple of days. These
environmental factors should cause the remnant low to dissipate in a
couple of days. This is also shown by the global model predictions.
The low has turned toward a slightly east of northward heading, and
the initial motion is about 010/7 kt. A north-northeastward motion,
ahead of an approaching frontal system, is expected over the next
day or so. The official track forecast is adjusted a little to the
left of the previous one, toward the latest model consensus.
For additional information on the remnant low please see High Seas
Forecasts issued by the National Weather Service, under AWIPS
header NFDHSFEPI, WMO header FZPN02 KWBC, and on the web at
http://www.opc.ncep.noaa.gov/shtml/NFDHSFEPI.shtml.
FORECAST POSITIONS AND MAX WINDS
INIT 28/0900Z 22.4N 122.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
12H 28/1800Z 23.3N 122.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
24H 29/0600Z 24.5N 121.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 29/1800Z 25.8N 121.2W 15 KT 15 MPH...POST-TROP/REMNT LOW
48H 30/0600Z 27.5N 121.0W 15 KT 15 MPH...POST-TROP/REMNT LOW
72H 31/0600Z...DISSIPATED
$$
Forecaster Pasch